The prior art foam and resin mixing devices have been large, bulky, unwieldy to handle and difficult to operate. In addition, prior art devices have lacked suitable controls so that simplicity of manual operation may be attained and whereby accurate dispensation and mixing of resins and foaming agents may be accomplished. Further, prior art devices have been difficult to maintain due to the requirement for maintenance, such as cleaning the resin from complex areas of the devices of the prior art.
In various devices of the prior art commonly used for spraying mixtures of foaming agent and urea formaldehyde, a great many tubular parts and valves have been assembled into large bulky configurations and these devices have been difficult to operate, as well as to carry and handle, during the placement of foam material and further, these devices have been difficult to maintain due to the fact that the resin has set up in them throughout the various areas such as the mixing chamber or the like and when the resin reacts and sets up in the prior art devices they are very difficult to maintain and it is always important that such devices be immediately cleaned after use due to the fact that the resins start to react and set up into a hard block of foam in the various passages of the prior art devices.